India, April 28 -- If someone asked what I'd bring to a deserted island, a white button-down shirt would be high on the list, which sounds dramatic until you realize it works for nearly every travel scenario short of actual survival. It may not be the most exciting piece in your suitcase, but it's easily the most reliable-and one fashion editors, stylists, and frequent travelers consistently reach for.

No matter where I'm headed, a beach vacation, a city trip, or somewhere in between, it's always the first thing I pack and the piece I end up wearing the most. It layers effortlessly on a flight, pairs seamlessly with office-ready staples, and dresses up easily for dinner, all without taking up much space. I styled it six different ways be...